The problem of domestic cats killing wild birds is enormous. It is estimated that 4.4 million songbirds are killed by domestic cats each day in the United States alone. That statistic, coupled with the continual destruction of wildlife habitat which further depletes bird populations, shows a great need for means for preserving the wild bird population. This problem is documented in the following references: Richard Stallcup, "Cats: A Heavy Toll on Songbirds. A Reversible Catastrophe," Point Reyes Bird Observatory Observer 91 8 (1991); P. B. Churcher and J. H. Lawton, "Predation by domestic cats in an English village", J. Zoology 211 439 (1987).
Presently the only method for completely preventing a domestic cat from killing birds has been to keep the cat indoors. This is a solution that a majority of cat owners do not find agreeable, therefore few of them keep their cats indoors. The attitudes of pet owners are as hard to overcome as a cat's natural hunting instincts.
Another less than satisfactory method for preventing bird predation by a cat has been to put a bell on the cat's collar. The sound of the bell is thought to warn birds of an approaching cat and give them time to escape. In actuality "belling the cat" does not work well if at all, since many new birds may come into an area that are unaware of the meaning of the bell and often the cat learns to stalk in a way which keeps the bell silent. Nor has it ever been clearly established that birds specifically associate the sound of the bell with a cat.
Another method that has been used to try to prevent bird predation by a cat is fencing the cat away from areas frequented by birds, such as near a bird feeder. Bird feeders are meant to attract birds and naturally cats are attracted to areas where birds often are. Due to the cat's prowess in leaping and climbing, fencing cats away from the feeder is often quite ineffectual. Often people face the choice of either having a cat or feeding the birds. However feeding birds and not owning a cat is not a solution, since a bird feeder will attract other neighborhood cats as well. Even when fencing around the bird feeder is effective, some birds are likely to stray out of the fenced bird feeder enclosure and into the close range of a cat. Then too, many people consider a fenced bird feeder unattractive and difficult to access, and will therefore not use this method for preventing cat predation of birds.
Placement of the bird feeders in a location impeding cats from getting close to the feeding birds has also been tried. One such location for the bird feeder might be high off the ground, but this does not prevent ground feeding birds from gathering to eat spilled seed and thus landing within the range of a waiting cat. An adjunct to high placement of the bird feeder might be locating it away from bushes or other objects that a cat could use to hide behind. This may reduce the bird killing somewhat, but cannot be considered an effective preventive measure.
One partial solution to the problem of cats killing so many birds would be a reduction of the number of cats. It is estimated that there are 60 million cats in the United States. Humane Societies and animal shelters are barely able to keep up with the numbers of unwanted cats (and dogs). Tragically many of the public are reluctant to neuter their pets and by not doing so drain public resources required to deal with the resultant pet over-population problem. The over-population of cats contributes to the large numbers of birds killed by cats.
A long standing need therefore exists to provide a solution to the problem of bird predation by domestic cats which would be acceptable to and widely implemented by cat owners.